PROJECT SUMMARY In this R34 application (PAR-18-276, Formative and Pilot Intervention Research for Prevention and Treatment of HIV/AIDS), we propose to develop and pilot test a primary HIV prevention intervention to address the dual and interconnected risks of HIV and intimate partner victimization (IPV) in transgender women (TW). TW are among the populations most heavily affected by HIV in the United States (US) and are at elevated risk for intimate partner victimization. Despite the dual and interconnected risks of HIV and IPV among TW, there are few empirically based HIV prevention interventions that target TW, and none that target HIV risks related to IPV in this population. The purpose of this treatment development research is to develop and evaluate the feasibility, acceptability, safety, and initial effects of a brief intervention that concurrently targets HIV and IPV risk, as well as that addresses inter-related risks of HIV and IPV (e.g., substance use and PTSD) for TW. The proposed intervention will be based on the Gender Affirmation Framework, which emphasizes interpersonal processes to positively affirm the identities and unique needs of transgender people, and will also integrate a trauma-informed empowerment approach, which is the model of choice when working with survivors of IPV. The intervention is hypothesized to reduce HIV risk within the context of IPV and related risk factors (e.g., substance use and PTSD), and to improve a range of primary prevention behaviors such as condom use, pre- exposure prophylaxis (PrEP), and repeat HIV testing. Importantly, the intervention will provide TW with behavioral skills and resources for addressing IPV and maximizing personal safety. We will use a three-phase research approach to address our specific aims. First, we will conduct formative qualitative research to develop an intervention training manual for HIV-IPV prevention and fidelity scales for monitoring implementation. Second, we will conduct an open pilot to refine and finalize the intervention manual and research protocol. Third, we will conduct a randomized pilot trial to test the HIV-IPV intervention compared to a time and attention matched control. Participants in the pilot trial will be followed over 6 months. We will assess intervention effects on primary outcomes including a composite indicator of biomedical and behavioral HIV risk as well as IPV safety; secondary outcomes including STI diagnoses (including HIV), as well as prevention behaviors: condomless sex, PrEP uptake, mutual monogamy with a virally suppressed partner, and IPV frequency. We will also examine mechanisms of change relevant to the theoretical foundations of the intervention, including gender affirmation, empowerment, and self-efficacy. The findings from this study will provide the necessary groundwork to examine the efficacy of this combined HIV-IPV intervention in a future, large-scale clinical trial.